The basic steps in a nutshell are something along the lines of:
Restore entrypoints to homebrew through browserhax.
Backup nand, create an emunand with the gateway launcher dat tool, restore nand, and unlink nands if desired.
Install ctrbootmanager to launch rxtools which boots emunand without signature checks.
Boot into HB from emunand and install FBI to emunand so you can easily install cia files.
Install cia files to have games on emunand.
Update emunand if desired. Only considered safe if nands are unlinked and done through system settings directly being booted into from emunand.